chill;608578 Wrote: > We should take care not to let this thread fork into another discussion > of soundcheck's mods, but I think it's worth noting that a possible > reason for differing opinions on the importance of the connection type > could simply be that some people are using the RCA analogue outputs, > and some are using a separate DAC. If you're using a DAC that's robust > against jitter and RF interference, then it really doesn't matter how > you get the bits to the player. If you're using the RCA outputs, then > all sorts of other things can possibly come into play. > > I'm not sure that enough reports have been explicit about setup to be > able to draw conclusions about what's a typical experience.
There's no doubt that the correct bits get to the player's buffer no matter what transport mechanism is used to get them there. But at any point in the signal path during or after the conversion to analog, there can be an impact of power supply noise on the quality of the analog signal, as well as RF pick-up from the built-in WiFi transmitter on PCB traces on a few cm away from the WiFi antenna. Once RF pick-up at 2.4GHz does occur, it could easily be subject to parasitic rectification due to any semiconductors in the signal path that have a square-law term to their non-linearity. WiFi signals are not constant amplitude, unless you are using 802.11b, so some AM conversion to audio is possible from the very close proximity WiFi antenna. So, I would say there are plausible mechanisms within the laws of physics for sound to be different with WiFi turned on vs. off. Also, if the processor load changes the drain in the power supply, the ideality of the d.c. power supply may change in terms or residual ripple and digital hash, not withstanding that separate digital and analog power supply regulators are used to isolate them as much as possible. However, it should be noted that Stereophile's measurements did not indicate any real sign of trouble, when looking for low levels of noise and jitter. http://www.stereophile.com/content/logitech-squeezebox-touch-network-music-player-measurements JA states at one point: "Finally, the Squeezebox Touch's jitter performance remained unchanged, whether it was playing the 16-bit diagnostic Miller-Dunn tone via WiFi or stored on a USB-connected drive." Of course, he did not try ethernet, but the impact of WiFi being in use on these very sensitive measurements seems to be very well controlled indeed. Figure 9 is measured with WiFi being used as the data source. JA didn't specifically go looking for differences between the performance between the three interfaces (WiFi, ethernet and USB), but he notably didn't find anything adverse to publish about the performance using the (arguably) more vulnerable of these. -- dsdreamer ---------------------- "Dreamer, easy in the chair that really fits you..." ------------------------------------------------------------------------ dsdreamer's Profile: http://forums.slimdevices.com/member.php?userid=12588 View this thread: http://forums.slimdevices.com/showthread.php?t=85420 _______________________________________________ Touch mailing list Touch@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/touch
